“担任向导”常见的英文表达有 serve as a guide、act as a guide 或 function as a guide。
serve as a guide：强调起到向导的作用。例如：He served as a guide for the tourists during their trip.（他在游客旅行期间担任向导。）
act as a guide：侧重于表示像向导一样行动、履行向导的职责。例如：The local resident acted as a guide and showed us around the old town.（当地居民担任向导，带我们游览了老城区。）
function as a guide：意思是发挥向导的功能。例如：This device can function as a guide for the visually impaired.（这个装置可以为视障人士发挥向导的作用。 ）